This invention is directed to a method and apparatus for efficiently conducting the repair operation of the lining of a furnace constructed by the DH degassing method or the RH degassing method.
Great improvements in the field of degassing methods of refining molten metal or steel have been observed in the past few decades.
Among all the degassing methods, the method and apparatus for repairing furnace linings according to the present invention is applicable to the furnaces constructed by the DH degassing method or the RH degassing method. The above two degassing methods are briefly explained hereinafter.
The DH degassing method was developed by Dortmund Hoerder Huettenunion A.G. of West Germany around 1956. This method utilizes a vacuum vessel hereinafter referred to as a DH furnace which is characterized by having a suction tube vertically and integrally attached to the bottom of the DH furnace. In the degassing operation, the ladle in which the molten steel is charged is carried to a position immediately below the DH furnace. After immersing the distal end of the suction pipe into the molten steel, the vacuum within the DH furnace is increased so that the molten steel is sucked up into the DH furnace and is degassed. Then by either lowering the ladle or raising the DH furnace, the degassed molten steel returns to the ladle and is mixed with the molten steel within the ladle. The degassing operation is completed by repeating the above sucking and discharging operation 30 to 35 times.
The RH degassing method was developed by Heraeus Co., Ltd. of West Germany and was put into practice at Reistahl steel refining plant. This method utilizes a vacuum vessel hereinafter referred to as an RH furnace, which is characterized by having a suction tube and a discharge tube which are both attached to the bottom of RH furnace. In the degassing operation, the ladle in which the molten steel is charged is carried to a position immediately below the RH furnace. By introducing the inactive gas Argon into the suction tube, the molten steel is drawn up into the RH furnace through the suction tube and is degassed. The degassed molten steel then returns to the ladle through the discharge tube. The degassing operation is completed by repeating the above circuiting two or three times.
The repairing operations of the furnace lining of the above-mentioned DH durnace or RH furnace have been conventionally conducted manually and are subject to the following disadvantages:
(1) The operation has required several operators who are specialists respectively in the spraying operation, device manipulation, and the DH furnace manipulation. PA1 (2) A blind spraying operation is conducted on the throat portion or the inner periphery of the suction tube since higher locations cannot be observed due to the possibility that refractory material or other high-temperature material such as remaining molten steel may fall onto the operator. PA1 (3) The operation of connecting the spray nozzle, and the piping or hoses has required a great deal of time. PA1 (4) The work must be conducted under an extremely hot furnace from which some adhering material may fall down, and therefore the operation involves very dangerous work.
Accordingly, it is an object of the present invention to overcome the aforementioned disadvantages by providing a method and an apparatus for automatically spraying refractory material onto a desired area such as the abraded or eroded portions of DH or RH furnaces.
It is another object of the present invention to provide a method and apparatus for automatically spraying refractory material onto a desired areas such as the abraded or eroded portions of DH or RH furnaces which are characterized by the use of a vertical spray pipe with a spray nozzle on the top thereof that is capable of being elevated and rotated on a transport car, whereby the spraying operation can be conducted with precision due to the mobility of the spray pipe.
It is still another object of the present invention to provide a method and apparatus for automatically spraying refractory material onto a desired area of DH or RH furnaces which is further characterized by having a cone-shaped recovery hopper around the spray pipe so that if extremely hot material such as any remaining molten metal or sprayed refractory material which cannot adhere to the inner surface of the furnace falls down, it will be collected in the hopper and will result in a highly safe and efficient spraying operation.
It might also be noted that the present invention may be used on other types of furnaces so long as the furnace can be repaired with a vertical spraying operation.
Other features which are considered characteristic of the invention are set forth in the appended claims.
Although the invention is illustrated and described in relationship to specific embodiments, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with accompanying drawings.